The 0z GFS had a monster storm system form along the East Coast in an event that would have decimated the region with more than 2 feet of snow and a monster cold outbreak just behind the system that would have brought freezing temperatures down to the Gulf Coast.
The 6z GFS had a similar set-up, but took the storm into Canada while leaving the cold outbreak to sink south just like the 0z GFS. Not as far south, but still down into Georgia and Alabama, among others.
The 12z GFS is the anomaly to these 4 model runs, as it took the storm to New England and pulled the cold air with it (out to sea) in unusual fashion. Additionally, unlike the 0z and 6z model runs, this forecast had the event happen 2 days later, on December 12th.
Luckily, the 18z GFS erased any hopes of a 12z GFS occurrence, but changed the storm track as it brought a strong system into the Midwest and Great Lakes, with snow hitting those same areas. Cold air did not have time to flow south, as another storm system was right on its heels.
Now, the GFS model alone in the long range is equivalent to playing with fire- you must be VERY careful with it, or you will get burned (i.e. disappointments after a storm does not happen). However, considering this has now been at least 4 model runs in a row that have showed some form of storm system and subsequent cold outbreak in the Lower 48, this does catch my eye. The GFS has been known to catch trends when certain events come back in forecasts over and over again, like the 4 examples shown above.
I will watch this system and provide updates as necessary, but this is a wait-and-see moment for now.